In the polyurethane industry there is a need for a delayed action catalyst, i.e. a catalyst that will delay the onset of the isocyanate-polyol reaction ("initiation time") while not substantially affecting the time to the end of the reaction or final cure, or that will yield the same initiation time with a shorter cure time. The problem is manifested in the production of polyurethane shoe soles where it would be desirable if the polyurethane forming composition would not begin to react until it has essentially filled the mold form while also reaching a final cured state in substantially the same or shorter time period to maintain productivity.
Past attempts to solve this problem have centered around taking the standard amine catalyst, i.e. triethylenediamine, and blocking it with an acid to form the simple amine salt. In theory, this approach should work well but from experimentation it failed to delay the initiation time as desired without lengthening the cure time.
U.S. Pat. No. 4,040,992 discloses the polymerization and condensation reactions of organic isocyanates are catalytically promoted by the use of N-hydroxyalkyl quaternary ammonium carbonylate salts, for example, N-hydroxypropyl trimethyl ammonium salts of carboxylic acids such as those of formic and acetic acids and of fatty acids such as hexanoic and octanoic acids and the like.
U.S. Pat. No. 3,892,687 discloses certain acyclic quaternary hydroxyalkyl ammonium alkoxides and phenoxides useful as catalysts for making polyurethane and polyurethane-polyisocyanurate foams.
U.S. Pat. No. 3,993,652 discloses phenoxides of certain cyclic quaternary ammonium bases containing a hydroxyalkyl group attached to the hetero nitrogen as catalysts in reactions involving organic isocyanates.
U.S. Pat. No. 4,116,879 discloses the preparation of cellular polyurethane resins using as a catalyst certain quaternary hydroxyalkyl tertiary amine bases.